At the present time, organic light emitting diodes (LED) are becoming very popular because of the large number of materials that are available as well as the relatively low cost of the organic materials and the ease of producing the materials in a workable form. However, one of the main difficulties with organic LED displays comes in the patterning of the organic material into separate LEDs.
One proposed method of patterning to form strips of organic material includes the use of vertical shadow masks, or upright walls, with organic material evaporated and angularly directed at the walls to form the separate strips. Additional information on this method of fabricating organic LED displays is disclosed in U.S. Pat. Nos. 5,276,380, 5,294,869, and 5,294,870.
The problem with most of these fabricating methods is that they are only viable for crude dimensions. Also, the upright walls are relatively difficult to form and position correctly. Further, because all of the various color devices are fabricated in an integrated process, many of the steps in these fabricating processes produce overlapping layers that can reduce efficiency of the final devices.
Also, organic light emitting diodes are sensitive to the presence of oxygen and water vapor in the ambient air and must, therefore, be hermetically sealed for proper operation and a useful longevity. Conventional hermetic seals, including metal cans, thick patterned metal and continuous insulating barrier layers are generally too large and cumbersome for large matrices. Further, once the organic materials are in place they are sensitive to high temperatures and it is generally difficult to find low temperature dielectrics that are a good hermetic seal.
Accordingly, it would be desirable to devise a fabrication process in which an organic light emitting diode display, and especially a color display, can be easily, conveniently and accurately produced and passivated.
It is a purpose of the present invention to provide a new and improved method of fabricating organic LED matrices.
It is also a purpose of the present invention to provide a new and improved method of passivating organic LED matrices and the like.
It is another purpose of the present invention to provide a new and improved method of fabricating and/or passivating organic LED matrices which is relatively easy and inexpensive.
It is still another purpose of the present invention to provide a new and improved method of fabricating organic LED matrices which is capable of producing relatively accurate items of material for high resolution displays.
It is a further purpose of the present invention to provide a new and improved method of fabricating and/or passivating organic LED matrices which is capable of producing matrices with reduced weight and thickness.
It is a further purpose of the present invention to provide a new and improved method of fabricating and passivating organic LED matrices in one lithography and using a single integrated mask.